:30 Psyche [February 



far as I am aware, occurs exactly in that fashion only in the 

 Homoptera and Psocids, the nature of the thoracic terga and 

 wing bases, the nature of the tarsal segmentation, and other 

 regions of the leg, the nature of the abdominal segments in 

 general, the segments of certain males and the ovipositors of 

 certain females in particular, and many other features too 

 numerous to mention at this point, all clearly indicate so close a 

 relationship between the Psocids and Homoptera, that it would 

 be stretching the laws of probability and chance far beyond the 

 breaking point to claim that the marked similarity in all of these 

 structures from all parts of the body, and extending through a 

 wide-ranging series of forms, is merey the result of "conver- 

 gence," and it would be very interesting to learn from those who 

 continually cry "convergence" whenever similarities are pointed 

 out between the Psocids and Homoptera, just how "convergence" 

 could be brought about in so wide a range of forms and in such a 

 multitude of details from all parts of the body! That the many 

 similarities in structures from other parts of the body extend 

 to the venation of the wings as well, in the Psocids and Homop- 

 tera, is shown in the series of insects figured in Figs. 17 to 24, which 

 includes some of the most primitive, and the most highly special- 

 ized, as well as the intermediate types of venation, in the two 

 groups of insects. Thus, the peculiar "broken" character of the 

 venation of the apical portion of the Psocid wing shown in Fig. 24 

 is paralleled by the wing of the Homopteron shown in Fig. 23, al- 

 though the fore wing of the Homopteron Cercopis sp., figured by 

 Handlirsch, 1909, would have been better for a comparison with the 

 Psocid shown in Fig. 24, than is the case with the Homopteron 

 shown in Fig. 23. The broader more primitively veined Psocid wing 

 shown in Fig. 22 is paralleled by that of the Homopteron shown 

 in Fig. 21, and the venation in the two is quite similar. Turning 

 next to the intermediate type of venation shown in Fig. 18, 

 it is quite evident that the Psocid shown in Fig. 18 is approached 

 by the Homopteron shown in Fig. 20, especially in the char- 

 acter of the anals, and the branching of cubitus and media, 

 which is strikingly similar in the two groups of insects, and there 

 Is evidently a tendency toward the formation of a pterostigma 



